How to Avoid Common Pool Maintenance Mistakes

Whether you’re a new pool owner or have owned one for years, proper pool maintenance ensures your inground pool remains a sparkling oasis, extends its lifespan, and minimizes costly repairs. If you’re a fiberglass pool owner, you probably have heard that fiberglass pools are the lower maintenance option among pool types. However, lower maintenance does not mean no maintenance. The following tips can help you avoid the common mistakes people make when caring for their inground pool.

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Whether you’re a new or seasoned pool owner, proper pool maintenance ensures your inground pool remains a sparkling oasis, extends its lifespan, and minimizes costly repairs. Fiberglass pools feature the lightest regular maintenance demands among all pool types, but “low maintenance” does not mean “no maintenance.” Taking a proactive approach and following a few simple tips can help you avoid common—and costly—pool maintenance mistakes.

Tip 1: Balance Your Water with Fiberglass in Mind

Failing to monitor water chemistry appropriately is one of the most frequent and frustrating mistakes pool owners make. Your pool water may look crystal clear, but that doesn’t mean its chemistry is in proper balance. Poor water chemistry balance can silently cause scaling, chalking, and permanent damage to your fiberglass pool’s surface.

To achieve water chemistry balance, fiberglass pool owners must focus on the factors that matter most:

• Maintain pH between 7.2 and 7.4.
• Keep calcium hardness less than 120 ppm. If calcium hardness reaches more than 120 ppm, use a chelating stain and scale control product.
• Chlorine should stay between 1 and 3 ppm.
• Use a stain and scale control product consistently.

Rather than relying solely on the Langelier Saturation Index (LSI), originally intended for concrete pools, proper fiberglass pool care depends on tight control of a few core values. By carefully managing calcium levels and avoiding high pH, especially in salt pools, you’ll help preserve the beauty of your gelcoat finish for the long term.

Use a high-quality test kit for the best results, or have your water tested professionally. Just be sure to take in water samples for testing promptly—exposure to heat, or a delay with the water sitting in a car for a few hours, can alter results.

For the most information and recommendations, refer to Thursday Pools’ Fiberglass Pool Care Guide and Owner’s Manual, which outline more details, target ranges, and chemicals to avoid.

Tip 2: Backwash Regularly

Many pool owners begin each swim season backwashing filters once per week, but frequency often fades as the summer progresses. Your filter plays an essential role in the continued enjoyment of your pool. Proper backwashing can reduce pool maintenance costs in the long run and encourage a healthy pool experience.

• Efficiency: A clean filter is more effective at trapping debris. A clogged filter cannot perform efficiently, putting more strain on your pool pump and reducing the equipment’s service lifespan.
• Water Quality: Frequent backwashing helps maintain clear and sanitary pool water. A dirty filter can harbor bacteria and allow more contaminants to circulate through the pool.
• Damage Prevention: Regular backwashing helps prevent issues from dirty filters or excessive pressure that can cause long-term damage to the pool’s filtration system.

A clean, efficient filtration system improves overall water quality and helps keep your pool water looking and feeling great.

Tip 3: Keep Up Your Water Level

Maintaining the water level at the midpoint of the skimmer opening allows your pool’s systems to operate correctly. The skimmer pulls debris from the pool’s surface before it sinks to the bottom of the pool, where it becomes harder to remove. If the water level is too high, the skimmer door may not work correctly, reducing its efficiency at collecting surface debris. If the water is too low, the skimmer may suck in air, which can lead to airlocks or damage the pool pump by causing it to run dry.

A proper water level also promotes balanced circulation. The pool pump must pull water through the skimmer for filtration and chemical treatment. Maintaining the correct water level helps ensure water circulates, distributes chemicals evenly, and keeps the temperature consistent.

With fiberglass pools, maintaining a proper water level is also critical to prevent structural stress. Extremely low water levels can lead to wall bulging or floating due to groundwater pressure, which is why most manufacturers’ warranties are void if owners allow the water level to drop below the skimmer.

Protect your pool’s structure by consistently checking and maintaining your water level.

Tip 4: Be Selective About the Pool Chemicals You Use

Not all pool chemicals and tools are safe for fiberglass pools. Mistakenly using the wrong products can lead to staining, discoloration, and surface damage.

Good Chemicals for Fiberglass Pools

• pH Balancers: Keeping the pH level between 7.2 and 7.4 is crucial. To maintain this balance, use pH increasers (soda ash) or decreasers (muriatic acid or sodium bisulfate).
• Alkalinity Increasers: Baking soda (sodium bicarbonate) can help keep total alkalinity between 80 and 120 ppm to stabilize pH levels.
• Non-Copper Algaecides: Look for polyquat algaecides, which are a safe alternative for fiberglass pools.
• Most Chlorine Types: Keep total chlorine at 1 to 3 ppm. When your water’s chemistry is in LSI balance, you will need less chlorine. High chlorine levels (more than 5 ppm) can damage the gelcoat finish.

Harmful Chemicals for Fiberglass Pools

• Calcium Hypochlorite: Completely avoid calcium hypochlorite, which is a form of chlorine that contains calcium, as well as calcium increasers and other products that contain calcium.
• High-Strength Chlorine: Avoid “shocking” the pool with high doses of chlorine, which can lead to discoloration and damage to the fiberglass surface.
• Copper-Based Algaecides: Avoid algaecides that contain copper, as they can damage fiberglass surfaces with blue-green stains that are difficult to remove.

Good Tools for Fiberglass Pools

• Soft-Bristle Brushes: Use soft nylon brushes to clean the pool’s sides and bottom. Fiberglass surfaces are relatively delicate, and using soft brushes will prevent scratches.
• Manual or Automatic Cleaners: Ensure your automatic pool cleaner is suitable for fiberglass pools.

Tools to Avoid with Fiberglass Pools

• Wire Brushes: Never use wire brushes or abrasive tools, which can scratch and damage the gelcoat finish.
• Heavy-Duty Vacuums: Some heavy-duty vacuums designed for concrete pools can be too abrasive for fiberglass surfaces.

Above all, the most significant pool maintenance mistake is not doing the necessary pool maintenance. Consistency is critical, so be sure to develop a regular and thorough schedule to keep your pool in great shape.

Looking for more information on fiberglass pool maintenance and mistakes to avoid? Explore Thursday Pools’ Ultimate Fiberglass Pool Maintenance Guide for a thorough look at everything you need to know.

And if you’re ready for personalized advice, connect with a local independent Thursday Pools dealer near you.

Frequently Asked Questions About Avoiding Fiberglass Pool Maintenance Mistakes

1. How often should I test my fiberglass pool water?

Test at least once a week during swim season, and more often if your pool sees heavy use or weather shifts. In the off-season, monthly checks help prevent chemistry surprises. Consistent testing and chemical adjustments helps prevent “invisible” damage like chalki

 

2. What happens if I let my fiberglass pool water level get too low?

Low water levels can cause air to enter the skimmer, damage the pump, and even stress the pool structure. Always keep the water halfway up the skimmer opening to protect your pool.

3. Can I use the same chemicals in a fiberglass pool that I would use in a concrete pool?

Not always. Avoid calcium-based chlorine (like cal-hypo), calcium increasers, and copper-based algaecides. These can cause staining or surface damage in fiberglass pools. Instead, use liquid chlorine, non-copper algaecides, and fiberglass-safe balancers.

4. How often should I backwash my pool filter?

Backwash when your filter’s pressure gauge reads 8–10 psi higher than its clean baseline, which is often about once per week during heavy use. Regular backwashing keeps your system efficient, your water clear, and your pump from unnecessary strain.

5. What cleaning tools are safe for fiberglass pools?

Use soft nylon brushes, microfiber cloths, and pool cleaners designed for fiberglass. Avoid wire brushes, stiff bristles, or heavy-duty vacuums that can scratch or damage the gelcoat surface.